Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

60 MIMICRY, ANTD OTItER PROTECTIVE
every one of them will be of some shade of ash or
-brown or ochre, such as are found among dead, dry,
or decaying leaves. The apex of the upper wings
is produced into an acute point, a very common form
in the leaves of tropical shrubs and trees, and the
lower wings are also produced into a short narrow
tail. Between these two points runs a dark curved
line exactly representing the midrib of a leaf, and
fromn this radiate on each side a few oblique lines,
which serve to indicate the lateral veins of a leaf.
These marks are more clearly seen on the outer portion of tile base of the wings, and on the inner side
towards the middle and apex, and it is very curious
to observe how the usual marginal and transverse
strime of the group are here modified and strengthened
so as to become adapted for an imitation of the
venation of a leaf. We come now to a still more
extraordinary part of the imitation, for we find representations of leaves in every stage of decay,
variously blotched and mildewed and pierced with
holes, and in many cases irregularly covered with
powdery black dots gathered into patches and spots,
so closely resembling the various kinds of minute
fungi that grow on dead leaves that it is impossible
to avoid thinking at first sight that the butterflies
themselves have been attacked by real fungi.
But this resemblance, close as it is, would be of little
use if the habits of the insect did not accord with it.
If the butterfly sat upon leaves or upon flowers, or
opened its wings so as to expose the upper surface, or